Dow Jones Map of the Market

Interactive real-time data visualisation

Physical Bar Charts

"In Physical Bar Charts, viewers are presented with five tall see-through tubes containing button badges, each with a specific message on. Visitors are prompted to help themselves to badges. As they do so, the levels in the tubes drop, presenting an inverse bar chart showing the popularity of the badges."

Something like this, hooked up to a set of weight sensors, could provide a nice analogue feedback loop.